Fatigue effects of marathon running on neuromuscular performance

The influence of an individual marathon race was investigated among 7 subjects who performed 2 types of unilateral isometric strength tests before and after the race. The tests included maximal isometric voluntary actions (MVA) of the knee extensor muscles and isometric endurance of 60% of pre‐marathon MVA. The results showed dramatic reductions of the maximal isometric torque (26 ± 14%) and endurance time (39 ± 9%). Maximal integrated electromyographic activity (IEMG) of the vastus medialis muscle decreased by 36 ± 26% and that of the vastus lateralis muscle by 42 ± 25%. In the submaximal endurance test, the post‐marathon isometric knee extension started at a higher level of IEMG and lower mean power frequency (MPF) for 6 of 7 subjects. These data suggest that the repeated stretch‐shortening cycles during the marathon race affected the force production by reducing neural input to the muscles and deteriorating the efficiency of the contractile mechanism.